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DelayAtlas

Route reliability record

IAHSNA

Houston to Santa Ana

Flights
1,094
Period
July 2025 to June 2026
Distance
1,346 mi
Carriers
1
A+GRADE

This route earns an A+. Close to nine flights in ten arrive inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 10 points better than the national rate of 77.6%. When something does go wrong the average delay runs roughly 55 minutes. That rests on 1,094 IAH to SNA flights, with a median arrival 10 minutes early.

Best time to fly IAH to SNA: a 8am–11am departure, ideally on a Tuesday. Flights in that window arrived on time 91.7% of the time and Tuesday flights 94.9%, against 87.2% for the route overall.

Set against the rest of the country, this route's record is 10 points better than the US average of 77.6%. That gap is worth roughly 96 fewer late arrivals for every thousand flights.

Key figures

On time

87.2%

Arrivals under 15 minutes late, of 1,082 completed flights

Avg delay

53 min

Across delayed arrivals only, not all flights

Cancelled

0.18%

National rate is 1.81%

Best carrier

United

87.2% on time across 1,094 flights

These figures cover 1,094 flights between July 2025 and June 2026. The median arrival is 10 minutes early, which is the part an average hides: most flights here are fine, and the on-time rate is decided by a tail of badly late ones. On-time means under 15 minutes late, the DOT's own threshold.

Carrier by carrier

Which airline is most reliable on IAH to SNA

Only one carrier clears this site's 365-flight floor here, so there is no comparison to draw. The table below is the full picture.

On-time performance by carrier on IAH to SNA
AirlineFlightsOn timeAvg delayCancelledGrade
United Airlines1,09487.2%53 min0.18%A+

Flight by flight

Flights on IAH to SNA

The flight numbers below flew this route at least 250 times in the period, busiest first. Each has its own record, with its schedule and delay causes.

Best ways to make this trip

The most reliable ways to fly Houston to Santa Ana

Every airline on this route and on the routes between nearby airports, ranked by how often a scheduled flight actually operated and arrived on time. 4 of the top 5 use a different airport at one end.

Most reliable ways to fly from IAH to SNA
OptionAirlineSuccessOn timeCancelledBest departureMost punctual flight
1. IAHLAXHouston to Los AngelesDelta Air Lines87.5%88.5%1.09%5am–8am, WedDL 1216 07:00
2. IAHSNAHouston to Santa AnaUnited Airlines87.0%87.2%0.18%8am–11am, TueUA 1383 09:30
3. IAHLAXHouston to Los AngelesUnited Airlines84.1%84.4%0.32%5am–8am, WedUA 2431 06:00
4. IAHLAXHouston to Los AngelesSpirit Airlines82.5%83.6%1.31%5am–8am, Tue
5. IAHLAXHouston to Los AngelesSkyWest Airlines77.9%78.3%0.49%2pm–5pm, Tue

Success is the share of scheduled flights that operated and arrived less than 15 minutes late, so a cancelled flight counts against it. “(route)” means the best time comes from every carrier on the route rather than this airline alone.

Plan this trip by month, day and time

Departure window

The best time of day to leave

Departure time is the single lever a traveller controls, and it moves the odds more than most people expect. Each bar below is the on-time rate for flights scheduled to leave inside that window, across 1,094 flights.

  • 5am–8am
  • 8am–11am365 flights91.7%
  • 11am–2pm364 flights84.5%
  • 2pm–5pm
  • 5pm–8pm1 flights
  • 8pm–5am364 flights85.4%

Scale runs 75% to 95%. Rows with fewer than 30 flights show a dash.

The weak window here is the middle of the day, not the evening: 11am–2pm runs 84.5% on time against 91.7% for 8am–11am. That shape usually means a departure bank rather than an accumulating delay, so the recovery later in the afternoon is real rather than noise. The 8am–11am window is the busiest, with 365 flights scheduled in it.

Across the year

When delays peak on this route

This route's year swings by 20 points from best month to worst, which is wide. An annual average tells you very little about the week you are actually flying, so read the strip rather than the headline if your dates are fixed.

On-time rate by calendar month91J94F93M89A83M76J80J84A88S87O85N97D
Darker means more delays. Figures are on-time percentages.December best, June worst

June is the worst month at 76.4% on time, 20 points below December, the best at 96.8%. Summer afternoon convection and peak-season schedules land on the same weeks every year, so this is a pattern you can book around rather than a run of bad luck. January was the busiest month here, with 93 flights.

Across the week, Tuesday is the strongest day at 94.9% on time and Sunday the weakest at 80.8%. 14 points is a smaller lever than departure hour, but it is free.

On-time rate by day of the week88.3Mon94.9Tue90.2Wed83.9Thu86.2Fri86.4Sat80.8Sun
Monday: 88.3 percent on time. Tuesday: 94.9 percent on time. Wednesday: 90.2 percent on time. Thursday: 83.9 percent on time. Friday: 86.2 percent on time. Saturday: 86.4 percent on time. Sunday: 80.8 percent on time

Delay causes

Why this route gets delayed

Carriers report a reason for every delay minute they cause, in five DOT categories. The split below is by minutes, not by number of flights, so a handful of very long weather delays weighs as much as many short ones. It covers 7,287 reported delay minutes.

  • Carrier
    40%
  • Late-arriving aircraft
    29%
  • Extreme weather
    16%
  • National Airspace System
    15%

Extreme weather accounts for 16% of delay minutes, well above the single-digit share typical across the system. Weather delays are lumpy: they arrive as whole bad days rather than as a steady drag, so the monthly strip above is the more useful view of the risk. The national share is 6%, so this operation carries roughly 2.6 times the usual weather exposure. The split is drawn from 7,287 reported delay minutes.

The largest share of delay minutes, 40%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. Unlike weather, that is a management outcome, and it is the category where the gap between two carriers on the same schedule is genuinely earned. It accounts for 2,902 of the 7,287 delay minutes reported here.

Cancellations are rare at 0.18%, below the national 1.81% and low enough to earn the plus on the grade. Roughly one flight in 100 is called off; the risk here is arriving late, not not arriving.

Connections and stage length

What a delay here actually costs

Badly late arrivals are rare here: only 3.6% land an hour or more behind schedule, against 8.1% nationally. Connections built on this flight are about as safe as US domestic connections get, though a cancelled flight still ignores every layover you give it.

The 1,346 miles between these two airports put this in the middle of the US network, around two and a half to three hours of block time. That is enough cruise to absorb a ten-minute late pushback and not enough to absorb thirty. It is also long enough that the aircraft usually flies three or four legs a day rather than six, which slows how fast delay compounds.

The return leg runs 87.9% on time across 1,094 flights, within half a point of this direction. The two legs are scored separately because they usually differ; on this city pair they happen not to.

One caution: this is a thin sample. 1,094 flights over twelve months is enough to clear this site's floor but not enough to pin the rate down tightly, and a single bad week moves it by more than a point. Treat the grade as a rough reading.

Work out the risk of missing a connection in SNA after this flight

What to do with this

Booking this route

Put together: treat all of this as provisional. 1,094 flights over twelve months is enough to clear this site's floor and not enough to be confident to better than a couple of points. The 87.2% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 1,082 completed flights over 12 months sit behind that.

Common questions

IAH to SNA questions

How often is IAH to SNA delayed?

About one flight in eight arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 12.8% of the 1,094 flights in this analysis, against 22.4% nationally. Delayed flights are late by roughly 55 minutes on average.

How reliable is IAH to SNA compared with the rest of the country?

87.2% of flights arrive on time here against a national 77.6%, a difference of 10 points in its favour. That is worth a A+ on this site's grading scale.

What time of day has the fewest delays on IAH to SNA?

The 8am–11am departure window is the strongest at 91.7% on time. The 11am–2pm window is the weakest at 84.5%, 7 points behind. Later departures inherit delays from earlier flights the same aircraft has already flown, which is why the curve slopes the way it does.

How bad are June delays on IAH to SNA?

June is the weakest month at 76.4% on time, compared with 96.8% in December. Across the year that is 20 points between the best and worst months. Moving flexible dates out of that month is one of the few things that reliably helps.

Related

Where to go next

Direction matters. IAH to SNA and SNA to IAH are scored separately because they are separate operations, with different departure banks and different aircraft. Compare the return leg.

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Source: US DOT Bureau of Transportation Statistics, on-time performance data, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.